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Wednesday, 9 November 2011

Examining the energy cost of Virgin Media's TiVo

After recently becoming a member of the Dual-TiVo club, I started to wonder how much energy that 2nd TiVo was using, and how much extra I would be paying on my electric bill.

So, how much does Virgin's Media TiVo cost to run?

The answer will partly depend on what cost your energy supplier charges you per unit for electric. 1 unit equals 1 Kilowatt hour (kWh). 1 kWh equals 1000 watts of electricity. A Kilowatt hour is the measurement of energy used by UK energy companies to charge customers on their bills.

Virgin's TiVo uses around 20 watts. Lets assume (for now anyway) that everyone gets charged what I do for 1 unit, which is 10p.

So, first we calculate the number of kilowatts used:

20 watts divided by 1000 = 0.02 Kilowatts

To get the Kilowatt Hours, we multiply the number of Kilowatts by the number of hours the device is on. So, assuming you're leaving your TiVo on 24 hours per day (which is recommended to receive EPG downloads, eagerly awaited software updates and of course, to, you know, record stuff from time to time), then:

24 hours x 0.02 Kilowatts = 0.48 kWh

And at 10p per unit/Kilowatt Hour, the daily energy cost of Virgin's Media TiVo is:

0.48 kWh x 0.10p = 0.048p per day

That means that leaving a TiVo box on all year will account for around £17.52 of your annual electric bill.

By comparison, V+ HD uses at least 27 watts (or it did before the recent software update which among other things, turned off the retina-burning halo lights in standby), and uses 0.648 kWh per day of electric, meaning a daily cost of 0.064p and a yearly energy cost of £23.36.

At first glance, both Virgin PVRs compare well against Sky+ HD, which (according to the user manual) uses an maximum of 45 watts, that's 1.08 kWh per day, that will cost you 0.108p per day and £39.42 per year. However, in standby its been reported that it uses around 18 to 19 watts, so it will cost you around the same as TiVo.

I think there's room for improvement as far as energy consumption is concerned for TiVo. At the moment, the hard drive is constantly spinning, even in standby. That's nice if you come in from work and you want to watch something which has gone into a tuner buffer but then, if that's the case, chances are you'll record that programme anyway.

V+ HD did the same thing for a while, until a software update automatically turned off the hard drive when it wasn't in use (cue sigh of relief from the UK's power stations). It would be nice if TiVo did the same thing, perhaps with an option to 'opt-out' of that feature in order to keep users who really want triple tuner buffering 24 hours a day.

5 comments:

I can live with £17.52 a year, much better than the huge amount the halogen lights in the kitchen cost to run (probably that a week)when they keep getting left on (8 lamps at 50 watts each !!!)

Interesting comment about the V+HD box, I thought mine was broken because the halo lights had stopped working. Pity the standby mode doesn't work properly, mine spins up every hour for around 2 minutes then shuts down again. At around 20 past the hour. As it's in the bedroom (Tivo in the living room), I've taken to unplugging it every night.